<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<script>
    function sum(i, j) {
        console.log("i=" + i + ",j=" + j)
        return i + j;
    }

    let f = sum  //将sum这个函数作为一个值赋值给变量f, 也就意味着sum函数表示的代码的值赋值给了f
    f(1,2)

    let r = sum(3,5)
    console.log(r)

    let k = f(3,6)
    console.log(k)
</script>
</body>
</html>